In an evolution process of Long Term Evolution (LTE), the project of LTE Rel-13 version had been researched since September, 2014, and one of important tasks is about the LTE system using an unlicensed carrier. This technology will enable the LTE system to use the current unlicensed carrier, which greatly improve potential spectrum resources of the LTE system and enable the LTE system to obtain spectrum at a lower cost.
However, the data transmission is performed in a LTE system by using the unlicensed carrier will face a lot of problems. Some of these problems are as follows.
On an unlicensed spectrum, besides the LTE/LTE-Advanced (LTE-A) system, other systems such as Wireless Fidelity (WiFi) and radar also exist. For fairness, each system needs to acquire resources in a competition manner, and the obtained resources need to be released after being occupied for a period of time. Therefore, LTE needs to efficiently utilize the obtained resources within limited occupation time.
If uplink data of a UE is transmitted on the unlicensed carrier, a base station or the UE needs to obtained resources by itself through competition, and the interval between the time for sending an uplink scheduling grant by the base station and the time for transmitting the uplink data by the UE is 4 ms. The spectrum resources have been released probably within this period of time, and therefore the utilization rate of the resources is low.
Therefore, the problems of discontinuous data transmission and low resource utilization caused by resource competition and resource occupation time limitations when transmitting data by using an unlicensed carrier exist in the related art.